Not really my area but this is interesting because it mirrors stuff I've read about shadow people activity near old industrial infrastructure. Like there's something about abandoned or disused human-made corridors that seems to attract... whatever these things are.
The railroad theory makes sense to me from a purely practical standpoint - the tracks create long straight lines through otherwise dense terrain, so you're more likely to actually see something at distance rather than just hearing it in the trees. Could be inflating the numbers a bit.
But the older theories about ley lines and energy corridors running parallel to old rail routes is worth looking into if you haven't already. Some researchers reckon the Victorians unknowingly built along existing natural pathways.
Anyone got specific locations? Curious if theres a pattern geographically or if its spread all over.